do not carry 'NC' or 'US' numbers and are outside the boundary of any incorporated municipality." Unlike highways in the primary system, secondary road numbers may be repeated multiple times throughout the system, provided that they are not repeated within the same county. For example, SR 2000 may refer to the physical roadway signed as Wake Forest Road or Falls of Neuse Road in Wake County, or it may refer to the physical roadway signed as Hickory Grove Road in Gaston County. Some road numbers are quite common. In fact, the designation SR1101 is currently used, or has in the past, been used nearly 100 times by almost every county in the state. Secondary roads that cross a county line are generally given a new number in the new county. For example, Rustic Court is a very short road, barely one tenth of a mile in length; yet, it crosses the Durham-Orange county line. The section in Durham County (0.03 miles in length) is designated SR 2397 while the section in Orange County (0.08 miles in length) is designated SR 1604. The exception to this rule applies to roads designated SR10xx, which are generally given to regionally significant roads or roads crossing one or more county lines, but which are not part of the primary system. For example, SR 1006 (Old Stage Road), is located both in Wake and Harnett counties. The significance of secondary road numbers is almost exclusive to NCDOT operations, generally maintenance, rather than for navigational purposes by the driving public. Certainly, the secondary road numbering system is not organized to help unfamiliar motorists find their way. Rather, this is the job of the road names, which are generally established at the local level, but which often share a sign with an SR designation for convenience. In some rural areas of the state, including parts of the Mountain and Coastal Plain regions, roads may lack a road name, in which case they are known by the SR designation. It is not uncommon for maintenance responsibility of secondary roads to transfer from NCDOT to particular municipalities as they increase in size due to annexation. When this occurs, the SR designations are eliminated. The SR road designation is also eliminated from physical roadways that are elevated into the primary system. For example, NC 157 (Guess Road) in Durham and Person counties was once a secondary road designated SR 1008.